1. Field of the Invention
The present invention refers to an arrangement and a method for using this arrangement for laying concrete floors on a hardened base.
2. Description of the Prior Art
Attempting to finds aids and methods for more rational construction is in every way a worthy aim. The procedure adopted for laying concrete floors against a hardened base, for example in factories, department stores, bridges, concrete floors in multi-storey buildings etc, is in principle as follows:
The surface on which the concrete floor is to be laid is divided, is possible, into rectangles of equal size. Half of these, distributed in a chessboard pattern, are laid the first day and the remainder are laid the second day. The reason for this is that the sides bounding these rectangular sections must be used as a screed guide support for the apparatus which is used for levelling and vibrating the applied concrete. Every second section must be given sufficient time to harden before the adjacent sections can be treated in the same way. The arrangement forming boundaries for the sides of the rectangular sections also act as barriers for the freely running concrete.
Before these guide supports are placed in position, certain preparatory work must be carried out. This consists of searching for a suitable material for use as a base for the concrete. The choice of base material is particularly important in, for example, factory buildings with large areas which can be subjected to considerable loads. Sand, which is an easily worked material with satisfactory drainage properties, is often used as a base on which the screed guide supports can be placed so that they are horizontal.
When the screed guides are in position, concreting can be carried out in the first-day rectangles, as described above. The concrete is poured in the rectangles in question and is levelled off manually. A light vibrating screed is then used for distributing and vibrating the concrete. This screed is supported on the screed guide supports which have been set up. When all the first-day rectangles have been processed in the manner described above, work is stopped to give the concrete time to harden until the next day.
The same screed guide supports can be used on the following day for proceeding in an analogous manner. When this work has been carried out, the concrete is permitted to harden until it has achieved sufficient strength to allow the screed guide supports to be removed. The voids thus created must be filled with concrete. This must be permitted to harden before the final treatment of the floor can be started. Such treatment normally embraces grinding and/or filling. Painting or other surface finishing treatment is then usually applied before the floor is taken into use.
This procedure for producing floors does not tally with the aim of rationalizing constructions. The present invention describes an arrangement and a method for avoiding the following troublesome disadvantages which result from the method described above.
Taking two days for concreting is a serious shortcoming in the method which is used today. The need to remove the screed guides and fill the voids which they leave with concrete also constitutes disadvantages. The German published patent application No. 1684389 indicates one means of avoiding this disadvantage by using the reinforcement in the floor to be cast as screed guide supports for the levelling screed. The disadvantage of this method is obvious since metallic objects very easily corrode. This will occur if the method is used and is probably the reason why it has never been generally accepted. It is, in fact very seldom used.
Swiss Pat. No. 545 393 indicates a means of placing prefabricated beams in a grind pattern so that the beams can be used as supports for concrete distributing machines of a type similar to that described above. This method has also been unsuccessful in gaining general acceptance on the market. It is easy to understand why since the beams are heavy and difficullt to handle. The concrete involves a considerable weight in itself and to this must be added the weight of the reinforcement used in the beams. A further disadvantage is that the welded mesh reinforcement, which is usually placed in the concrete to increase the loadbearing capacity of the floor, cannot be fixed in position in a satisfactory manner.
Another shortcoming which affects the current system is that it is difficult to place reinforcement which runs through the various rectangles with the purpose of preventing vertical movements in the finished floor.